Method for transmitting data in networks over data lines

ABSTRACT

Bandwidth of a data line of a network is subdivided into at least two portions before or during transmission so that, while a recipient is receiving data being transmitted to the recipient from a sender over a first portion of the data line, the recipient can transmit data to the sender or another device over free bandwidth on the other portion(s) of the data line.

BACKGROUND OF THE INVENTION

The invention relates to a method for transmitting data in networks overdata lines.

Methods for data compression have been known for some time and serve toreduce the volume of data before it is otherwise processed, so that itrequires less memory or can be transmitted more quickly overcommunication lines.

Thus the following examples are known processes applying currenttechniques:

EP 0 933 B76 describes a method of compressing and transmitting data inunreliably functioning networks. After the first communication betweentwo interacting terminals, Terminal 2 sends a defined algorithm for datacompression to Terminal 1. Data is compressed according to thisalgorithm and returned to Terminal 2, where data is unpacked accordingto the originally sent algorithm.

U.S. Pat. No. 5,822,524 describes a process for transmitting multimediadata, such as videos, in a network. Multimedia data is called up from aserver via a user terminal and sent compressed and digitalized in such away that the user terminal's buffer, which can normally save 1 to 5video images, is always full. Video data is thus not linked to acontinuous or medial data stream.

U.S. Pat. No. 5,564,001 also describes a method of transmittingmultimedia data in networks with limited bandwidth, which includestelecommunication cable networks. Here, multimedia data is separatedinto important and less important multimedia information according to apsychographics parameter. The data can thereafter be at least partiallycompressed. After transmission to the user, the compressed data isdecompressed and rejoined with the data which was sent in uncompressedform.

EP 0 852 445 discloses a method to optimize bandwidth for compressedmultimedia data streams for transmission in networks. Compressed datablocks are marked before being sent so that each block's marker includesthe data block's enclosed data volume, information relevant tocompression/decompression, and the point at which each data block is tobe reinserted into the entire data composite. In addition, before datatransmission, a server detects the recipient's minimum buffer capacityand minimum number of receivable data blocks. This information, combinedwith the transmission rate of the compressed data blocks, allowscalculation of an optimal stream of compressed data blocks to therecipient's buffer, and the compressed data blocks can be transmittedwith a specific minimum rate to keep the recipient's buffer running justbarely above idle. This transmission method guarantees transmission ofcompressed data blocks over an appropriate bandwidth, because availablebandwidth depends on the recipient's buffer capacity. A large receivingbuffer increases available bandwidth; a faster transmission ofcompressed data blocks ensues to prevent the buffer from idling and thusavoid momentary freeze images. In contrast, data block transmissiondecreases for a small buffer to prevent a superimposition of theindividual images.

The known methods of transmitting compressed data reduce data volume fortransmission by compressing data to be transmitted; however, they cannotprevent the fact that sender and recipient of this data have no accessto data available in the network during data transmission. The recipientis blocked for the duration of data transmission and incapable ofcommunication with other end devices or the central processing unit ofeach network.

Because data volume intended for transmission nevertheless continuallyincreases in networks (for example, extensive print jobs,high-resolution images, or multimedia data information), this problemcannot be ignored.

SUMMARY OF THE INVENTION

Therefore the object of the present invention is to develop a methodwith which an unhindered communication is secured for the data senderand/or recipient during transmission of voluminous data in a network.

This object is solved by the features according claim 16.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram depicting a network including a central processingunit Z and any number of end devices from E₁ to E_(n).

FIG. 2 illustrates an exemplary arrangement of sender and recipientconnected by a communication channel subdivided into two subchannels.

FIG. 3 is a flowchart illustrating steps of subdividing bandwidth anddata compression.

FIG. 4 is a flowchart illustrating steps of calibrating data packets tothe size of a buffer within a recipient.

FIG. 5 is a flowchart illustrating adaptation of compression algorithmsto data types.

FIG. 6 is a flowchart illustrating steps of simultaneously establishinga connection to an internet server and starting a print job on theinternet server by activating a print button.

FIG. 7 is a flowchart illustrating steps of controlling datatransmission depending on the status of a buffer on a recipient side.

FIG. 8 shows the use of a gateway for communication between a user ofboth an application server and a dedicated print server.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 2 and 3, the invention thereby prescribes thatbandwidth 102 is predefined 130 or at least divided 132 into two areasbefore 102, 104 before transmission in consideration of the network'savailable data line 100 for data transmission to each respectiverecipient 108, so that data can be transmitted 134 from sender 106 toeach respective recipient 108 over a predefined bandwidth 102 parallelto data reception 138. The recipient 108 can likewise send other dataover the free bandwidth 104 to the sender 106 or to other netparticipants while receiving data 138. After receiving data 138 areavailable for subsequent use 142 on recipient's side.

No predetermination of communication direction is set during thedivision of bandwidth into areas, so that data can be transmitted in anydirection and/or bi-directionally.

Data can also be compressed 136 before transmission to enable processingan even larger amount of data as necessary. For this purpose the sendingdevice 106 is equipped with means for data compression 110. Datacompression 136 is effected using known algorithms. The efficiency ofcompression using algorithms increases with the size of the data beingcompressed. For example data to be transmitted is compressed 136 beforetransmission 134 by the sender 106 and subsequently sent 134 over thedesignated portion 102 of bandwidth 100, and that the transmitted datais decompressed 140 by the recipient 108. For this purpose the receivingdevice 108 is equipped with means for data decompression 112. In apreferred embodiment of the invention the command to transmit data 144is given by recipient 108 to sender 106. In another preferred embodimentof the invention the command to transmit data 144 is given fromrecipient 108 by piloting a virtual port 116.

Referring to FIG. 4, multimedia data and print data are usually sentover an appropriate data line in a constant stream of relatively smallpackets. With the method according this invention, relatively largepackets are used, which can furthermore be optimally compressed. In apreferred embodiment compressed data is sent in a stream of data packetswith the largest volume possible 148. The speed of transmission is thusadditionally improved. This is achieved by sending buffer sizeinformation 152 to the sender 106, and calibrating data packets 146 tothe size of buffer 118 within recipient 108.

With this method, communication with the end device occurs under use ofthe end device's buffer 118, whereas data transmission occurs in packetswhich are calibrated 146 for the end device's buffer 118. Referring toFIG. 7, the transmission process is interrupted 174 if the end device'sbuffer 118 is full. The process restarts 176 once the buffer 118 isagain receptive.

Referring to FIG. 5, one embodiment of the invented method prescribesthat, after checking the type of data 158 to be transmitted, thealgorithms used for compression are specifically calibrated 160 to thetype of data to be compressed. It is thus possible to apply algorithmswhich are calibrated to the relevant printer language—e.g., PostScript,PCL, or RAW—for data output on a printer which hereby directly orindirectly represents the data recipient.

Algorithms specifically calibrated 160 to the type of data to becompressed also enable superfluous data to be filtered out 162, as whenan acceptable loss of quality is tolerated with multimedia data, whichfurther downsizes the amount of data to be compressed.

It is furthermore possible to send redundant data sequences one timeonly in compressed form to the recipient and to save it there, so thatrepeated transmission of identical data sequences is unnecessary. Thisleads to an increased improvement to transmission rate of compresseddata. This can occur in such a way that instead of the data sequence,which has already been sent once, a specific code can be sent 156, whichhas the effect at the recipient that the relevant data sequence isinserted 166.

Any network is suitable for the transmission of compressed data. Thisincludes fixed networks, networks combining fixed and mobile networks,and purely mobile networks. Networks should have a minimum bandwidth of9.6 kbs for optimal deployment of the inventive method. The inventivemethod is nonetheless also deployable in networks which do not fulfillthis requirement of 9.6 kbs.

The inventive method is preferably found in companies connecting totheir branch offices over external networks such as the internet usingmobile connections.

Data entry, e.g. accounting, is effected in the branch officesthemselves using data input means 114, whereby a host system isaccessed. Accounting vouchers are in turn printed in the respectivebranch office. Because this data is sent from the host system 106 to thebranch office 108 over a data line 100, a data line 100 using currenttechnique is occupied for a fairly long time with print data, so thatadditional account entry is impossible or at least difficult. With theinvented method, accounting transactions can henceforth be processedduring output of the print data via the predefined bandwidth 102. Printdata is transmitted 134 by user command 144 in the branch office 108through the host system 106, whereby the predefined bandwidth 102 isonly preset 130 indirectly over the host system 106 as sender, becausethe user of the computer in the branch office 108 (i.e., recipient ofthe print data) enters 144 the command for it. It is usually irrelevantto the user whether he is using his or the host system; the command“Print” is simply given for a print job, whereas depending on where thedata is stored, either the local computer or the host system forwardsthe data to the appropriate printer. With the invented method, print outensues over a virtual printer port 116 which the user can specificallycontrol.

Recipient 108 and sender 106 here are usually the computer in the branchoffice and the host system respectively, whereby other appropriate dataprocessing devices could also be used as recipient and sender.

Predefinition of the bandwidth allocated for transmission 130 of thecompressed data can be set manually or automatically, once orcontinually, and absolutely or in relation to the total availablebandwidth or in relation to the bandwidth necessary for transmitting thecompressed data. Manual predefinition ensues from the host system orfrom the end device. In a preferred embodiment bandwidth 102 is definedcontinuously or adjusted 154 during transmission causing subdivision ofthe bandwidth of data line during transmission 150.

As a rule a bandwidth 100 of 64 kbs is available for connection betweenbranch offices or subsidiaries and a host system. It is thus possible,for example, to manually preset 130 bandwidth 102 for transmittingcompressed data from the central processing unit 106 to an end device108 to 32 kbs, so that a bandwidth 104 of 32 kbs are still available forthe data stream from the end device 106 (as sender) to the centralprocessing unit 108 (as recipient).

If the network's maximum bandwidth 100 is unknown, available bandwidth102 can be preset 130 manually in relation to the maximum bandwidth 100;for example 50% of maximum bandwidth 100 can be reserved fortransmitting compressed data.

If the data stream from the central processing unit 106 to the enddevice 108 greatly overbalances the incoming data stream from end deviceto central processing unit, bandwidth can be set in relation to theamount of data to be transmitted. For example, 75% of maximum bandwidth100 for the data stream from central processing unit to end device andonly 25% for the data stream from end device to central processing unit.

Because manual predefinition requires knowledge of the maximum bandwidth100 or the amount of data to be transmitted, it is advantageous todefine 130 these settings software-controlled and thereforeautomatically.

Another optimization of the invented method is that the bandwidthsetting 130 is not conducted once but is checked by software at specificintervals or for every transmission of larger amounts of data and setaccordingly.

After compressed data is transmitted 134 from sender 106 to recipient108, it is there decompressed 140 with the algorithm used forcompression, if the data is not to be saved in compressed form.

If data is to be printed directly from a printer without beingtemporarily stored on a computer, the printer itself, which usually hassufficient memory available, can decompress the data 140; or an externalprint server can undertake decompression 140 and then forward the datato the printer.

Today it is usual for a user to preview 120 a document on the monitor119 of a computer before beginning a protracted printout of texts,graphics, etc. In the framework of a network architecture, in which theapplication is run on a remote server, this is not sensible becausetransmitting the page image is almost as time-consuming as sending thefinal printout to the printer. The user must then have two waitingperiods. According to the invented method, a provision is therefore madethat the page preview 120 is sent as data stream to the end user 108 anddisplayed there, whereby the data in this data stream can additionallybe used for printing the relevant page, making a second transmissionunnecessary.

Preferred data for transmission is multimedia or print data. Theinvented process is especially suitable for the transmission 134 ofenormous amounts of data. Computer games and above all network computergames which can be run with any number of participants, music, videos,books, files, or 3-D illustrations represent enormous amounts of datawhose transmission 134 can be managed using the invented method.

The invented method enables transmission 134 of amounts of data of anysize with appropriate compression of data volume and predefinition 130of a bandwidth 102 for the transmission 134, so that parallel networkaccess during data transmission 134 via the free bandwidth 104 canproceed unhindered.

Unhindered communication via the free bandwidth 104 with other enddevices during data transmission 134 is thus possible. The recipient 108can enter data into the net via the free bandwidth 104 while he isreceiving 138 a transmission 134 of compressed data via The predefinedbandwidth 102.

Amounts of data of any size can be called up from the internet via thepredefined bandwidth 102, for example, and magnetically or digitallysaved on each end device while “surfing” the internet can proceedunimpaired via the free bandwidth 104.

When data is requested from an internet server, the connection can onone hand be established both after receipt and before the next request.On the other hand, it is possible for the user to target the internetserver without giving his own address (IP masking), which is veryinteresting for security reasons and therefore often practiced. Theinternet server is then informed that the user is collectinginformation. For printing, the internet server must completepre-processing and then send the data stream to the end device, which itusually cannot address. Either the user keeps a constant connection opento the internet server, which leads to higher communication costs andbandwidth usage, or the user must constantly check if a print jobexists, which can be lead to corresponding disadvantages. Referring toFIG. 6, the method therefore advantageously provides a print button 122for internet applications, which by activating 168 the print button 122,automatically, simultaneously starts 172 the print job on the internetserver and prompts the end device to establish a connection 170 to theinternet server.

The invented method also offers the option of processing print datawithin the context of so-called web printing Here, print data is sentfrom the end device to a URL, which this method expands to two furthercomponents to stipulate the form of the print job and the targetaddress. Thus it can be stipulated whether the print job is sent as fax,SMS, e-mail, etc., and to which telephone number it should be sent. Inthis case it is possible for the computer found under the URL to senddata and receive the print data and to forward it as instructed.

Likewise, referring to FIG. 8, the invented method can be used as acommunications gateway 182 for dedicated print servers 180. Print jobsin networks are in general swapped out to print servers 180 forpre-processing for reasons of simplified administration. The end device108 must therefore have a connection to both the application host system178 as well as the dedicated print server 180. It is, however, moresensible to establish a single, secure connection to the internet forsecurity reasons. The method therefore provides that a gateway 182 canbe installed on the application host system 178 which reroutescommunication to the dedicated print server 180 so that it appears tothe use as if the print stream were coming directly from the applicationhost system 178. Thus the end user 108 only needs to establish a singleconnection 184 to the host system 178.

With one embodiment of the invented method, transmitted data is assigned164 to a user/end device in such a way that data consumption concerningthe number of printed pages, bandwidth reservation, bandwidth usage,data volume, and saved data volume can be registered and used forbilling purposes and for limitation of printouts according to the statusof each user account.

Additional advantageous embodiments are characterized in the sub-claims.

Hereinafter the inventive method will be exemplified with a diagram.

FIG. 1 depicts a network consisting of a central processing unit Z andany number of end devices from E1 to En. The end devices E1 to En areconnected with additional output or storage devices and an input unit,which are only represented for end device E1. E1 is connected with astorage unit S, an input unit T, a printer D, and a monitor M. Theindividual lines represent the data lines between end devices and thecentral processing unit.

CPU Z, on which as example a data base with music recordings is saved,is controlled across the network from E1. The user on E1 selects andretrieves several musical pieces. Now the multimedia data is compressed162 on CPU Z, 106 using an algorithm specifically calibrated 160 to thistype of data and bandwidth 102 is set 130 according to the amount ofdata to be transmitted. Now the compressed data is transmitted 134without influencing the user on E1 108. He can continue to be active inthe network without problem and himself enter data into it, because thedata stream from E1 to Z is undisturbed by the incoming data stream. Thedata sent to E1 is to be burned onto CD there. To do so, the data isdecompressed 140 on E1 108 and forwarded to the storage unit S, which inthe illustrated example is a CD burner.

Another practice could be as follows: Z 106 is a server in an in-housenetwork of a decentralized company on which entire customer files, allproduced wares, delivery amounts, delivery times, prices, etc., aresaved. E1 108 is a computer in a branch office. From there, allinformation about a certain product can now be called up; it's sent incompressed form from server Z 106 to end device E1 108 while theincoming data stream continues to be sustained. For example, orders canbe sent from E1 abroad to Z for central processing during transmission134 of compressed data from Z 106 to E1 108. The transmission 134 ofcompressed data is forwarded from E1 108 directly to a printer which,using software that has been specifically adjusted to the appliedprinter language, decompresses 140 and prints the received print data.Moreover, the transmitted data can be forwarded from E1 to a storageunit S, where it is saved in compressed form until the next update.

1. A method for transmitting data over a data line of a networkcomprising: providing a user end device coupled to the data line via aninterface, wherein a bandwidth for data transmission over the data lineis available at the interface, and the data line connecting the userdevice and a remote server; a user at the user end device starting aprint process on the remote server; before or during transmission offirst data generated by the print process on the data line of thenetwork, the user at the user end device coupled to the data lineentering a command for adjusting a data rate for transmitting the firstdata generated by the print process from the remote server to the userend device in order to subdivide the bandwidth of the data line at theinterface into at least two bandwidth portions, wherein the usercontrols the data transmission on the data line, and wherein a firstpredefined bandwidth portion of the at least two bandwidth portions ofthe data line is allocated to the first data generated by the printprocess to be transmitted in a first data transmission from the remoteserver to the user end device, and further wherein at least one secondbandwidth portion other than the first predefined bandwidth portion ofthe data line is adapted for transmission of second data in a seconddata transmission independent from the first data transmission, whereinthe at least one second bandwidth portion is usable for bidirectionaldata transmission.
 2. The method of claim 1 further comprising:compressing at least the first data to be transmitted over the data linebefore transmission by a sender; transmitting the compressed data to theuser over one of the at least two portions; and decompressing thetransmitted data at the user end device.
 3. The method of claim 2,wherein the compressing includes executing an algorithm corresponding toeach type of at least the first data to be transmitted and which atleast one of filters out superfluous data and effects optimalcompression.
 4. The method of claim 3 further comprising: transmittingto the user end device repetitive data sequences in at least the data tobe compressed only once in compressed form; and saving the transmitted,compressed data sequences at the user end device.
 5. The method of claim2 further comprising: transmitting to the user end device, having abuffer, data packets calibrated to the size of the buffer; interruptingthe transmission of the data packets to the user end device if thebuffer becomes full; and following the interruption of the transmission,resuming the transmission of the data packets to the user end deviceonce the buffer becomes receptive.
 6. The method of claim 1, wherein theuser provides to a sender a command to transmit the first data.
 7. Themethod of claim 6, wherein the user provides the command to transmit thefirst data by piloting a virtual port.
 8. The method of claim 1, whereinthe bandwidths for the respective at least two bandwidth portions arepredefined at least one of before the first or second data istransmitted and before each new data transmission.
 9. The method ofclaim 1 further comprising: continuously defining or adjusting thebandwidths of the respective at least two bandwidth portions duringtransmission of the first or second data over the data line.
 10. Themethod of claim 9, wherein the data line has a minimum bandwidth of 9.6kbs.
 11. The method of claim 2, wherein the compressed data is sent in astream of data packets with the largest volume possible.
 12. The methodof claim 1 further comprising: assigning transmitted data to the userend device such that data consumption concerning number of printedpages, bandwidth reservation, bandwidth usage, data volume and saveddata volume is registerable and usable for billing purposes and forlimiting printouts according to status of a user account.
 13. The methodof claim 1 further comprising: when a sender is an application host of adedicated print server, rerouting to the dedicated print server aprinting communication transmitted to the sender by the user.
 14. Themethod of claim 1 further comprising: transmitting a page preview to theuser end device as a print stream comprising the first data anddisplaying the page preview at the user end device; and using the firstdata of the print stream for print out.
 15. The method of claim 1further comprising: providing a print button to the user; and followingactivation of the print button by the user, automatically starting printout of print data located at the user end device and simultaneouslyestablishing a connection between the user end device and a sender. 16.The method of claim 1 wherein the transmission of the first datatransmission and the second data transmission is in parallel.